Buildings may account for about 40% of the total energy consumption and 38% of carbon dioxide emissions in the United States. Approximately 40% of the total energy consumed in both residential and commercial buildings may be used by Heating, Ventilation, and Air Conditioning (HVAC) systems. 10% to 40% of the energy used by the HVAC systems may be wasted due to faults, such as biased or drifted sensors, malfunctioning controllers, stuck dampers, and fouled coils. This waste in energy accounts for $36 billion to $60 billion every year in the United States. Increasing energy efficiency of HVAC systems may directly reduce utility costs for building owners, and may play a role in achieving sustainable environment. Many computerized approaches and algorithms have been developed to automatically and continuously analyze conditions of HVAC systems. However, the complex information required by these algorithms may pose a challenge in deploying them in real-world facilities.